VESICOURETERIC REFLUX IN ADULTS

Vesicoureteric reflux (VUR) in adults
VUR is the retrograde flow of urine from the bladder into the upper urinary tract with or without dilatation of the ureter, renal pelvis, and calyces. It can cause symptoms and may lead to renal failure (reflux nephropathy). In the UK, 25% of patients requiring haemodialysis or transplantation do so because of reflux nephropathy.

Pathophysiology
Reflux is normally prevented by low bladder pressures, efficient ureteric peristalsis, and the ability of the vesicoureteric junction (VUJ) to occlude the distal ureter during bladder contraction. This is assisted by the ureters passing obliquely through the bladder wall (the ‘intramural  ureter), which is 1 - 2cm long. Normal intramural ureteric length to ureteric diameter ratio is 5:1. VUR of childhood tends to resolve spontaneously with increasing age because as the bladder grows, the intramural ureter lengthens.

Classification
Primary: a primary anatomical (and therefore functional) defect where the intramural length of the ureter is too short (ratio <5:1).
Secondary to some other anatomical or functional problem:
- Bladder outlet obstruction (BPO, DSD due to neuropathic disorders,1 posterior urethral valves, urethral stricture) which leads to elevated bladder pressures.
- Poor bladder compliance or the intermittently elevated pressures of detrusor hyperreflexia (due to neuropathic disorders1 e.g. spinal cord injury, spina bifida).
- Iatrogenic reflux following TURP or TURBT (a tumour overlying the ureteric orifice) this is rare; ureteric meatotomy (incision of the ureteric orifice) for removal of ureteric stones at the VUJ; following incision of a ureterocele; ureteroneocystostomy; post pelvic radiotherapy.
- Inflammatory conditions affecting function of the VUJ: TB, schistosomiasis, UTI.

Associated disorders
VUR is commonly seen in duplex ureters (the Meyer - Weigert law).2 Cystitis can cause VUR through bladder inflammation, reduced bladder compliance, increased pressures, and distortion of the VUJ. Coexistence of UTI with VUR is a potent cause of pyelonephritis reflux of infected urine under high pressure causes reflux nephropathy, resulting in renal scarring, hypertension, and renal impairment.

Presentation
- VUR may be symptomless, being identified during VCUG, IVU, or renal ultrasound (which shows ureteric and renal pelvis dilatation) done for some other cause.
- UTI symptoms.
- Loin pain associated with a full bladder or immediately after micturition.

Symptoms of recurrent UTI or of loin pain may have been present for many years before the patient seeks medical advice. Even then it may take some time for a diagnosis of VUR to be made because a high index of suspicion is required and the definitive test for making a diagnosis of VUR (VCUG see below) is invasive (although VUR may be diagnosed by the less invasive use of IVU).

Investigation
The definitive test for the diagnosis of VUR is cystography. VUR may be apparent during bladder filling or during voiding (voiding cystourethrography, VCUG also known as micturating cystourethrography, MCUG). Urodynamics establishes the presence of voiding dysfunction (e.g. DSD) if this is suspected from the clinical picture. If there is radiographic evidence of reflux nephropathy check blood pressure, check the urine for proteinuria, measure serum creatinine, and arrange a 99mTc-DMSA isotope study to assess renal cortical scarring and determine split renal function.

Management
VUR is harmful to the kidney:
- In the presence of infected urine
- Where bladder pressures are markedly elevated (due to severe BOO, poor compliance, or high-pressure hyperreflexic bladder contractions)
In the absence of urinary infection or severe outflow obstruction/raised bladder pressures, VUR is not harmful, at least in the short term (months).
Subsequent management depends on:
- The presence and severity of symptoms
- The presence of recurrent, bacteriologically proven urinary infection
- The presence of already established renal damage (radiological evid-ence of reflux nephropathy, hypertension, proteinuria proteinuria is a poor prognostic factor in patients with VUR, indicating the likelihood of impending ESRF)

For the patient with primary VUR, recurrent UTIs with no symptoms between infections, no hypertension, and good renal function: treat the UTIs when they occur; consider low-dose antibiotic prophylaxis if UTIs occur frequently (say >3 per year). If the UTIs are regularly associated with constitutional disturbance (acute pyelonephritis rather than simple cystitis), then ureteric reimplantation is indicated.

For the patient with primary VUR and objective evidence of deterioration in the affected kidney (i.e. progressive radiological signs of reflux nephropathy or reduction in renal function): ureteric reimplantation.

Reflux into a non-functioning kidney (<10% function on DMSA scan) with recurrent UTIs and/or hypertension: nephroureterectomy.
Primary reflux with severe recurrent loin pain: ureteric reimplantation.
Secondary reflux:
- into a transplanted kidney: no treatment is necessary.
- VUR in association with the neuropathic bladder: treat the underlying cause relieve BOO, improve bladder compliance (options: intravesical Botox injections, augmentation cystoplasty, sacral deafferentation).

VUR with no symptoms, no UTI, no high bladder pressures and no BOO: the management of these patients is controversial because it is not known whether low-pressure, sterile reflux causes deterioration in renal function over many years without treatment. For grade I and II reflux (reflux of contrast into non-dilated ureter), it probably doesn't, and many urologists would not recommend surgery, but would monitor the patient for infection, hypertension, and evidence of deterioration in the appearance and function of the kidneys. For grade III or more it may do so, and many urologists would recommend ureteric reimplantation (or a STING procedure).